Liquid propellant rockets produce thrust by the combustion of a liquid fuel with a liquid oxidizer in a combustion chamber, in which the hot combustion gases exit to a nozzle exit cone assembly producing forward motion of the rocket motor. In the liquid propellant rocket motor, fuel and oxidizer are separated in different tanks. It is a common practice to use an expulsion system to pressurize the liquid fuel and the liquid oxidizer in order to force the materials into the combustion chamber. In previous applications, increases in fuel energy and fuel density have been achieved by use of a slurry of aluminum or other metal powder in the fuel carrier liquid. In many instances, the fuel carrier liquid is a hydrocarbon, a nitrogen containing material, which is a derivative of urea or hydrazine, or a liquid organo metallic fuel. An improvement to liquid propulsion rockets, has been achieved by the use of gelling techniques in which the liquid fuel and liquid oxidizer are gelled by addition of small percentages of very finely divided gelling agent, such as silicon dioxide powder, which converts the liquid into a gel. The advantages of gellation are due to the fact that these materials will not spill or run. The gels have the characteristics of semi-solids until they are pressurized. When work is put into the gel, in the form of pressure or vibration, the gel will flow with characteristics of a liquid.
Gelled propellant fuel such as a thixotropic rocket fuel comprised of monomethylhydrazine, metallic fuel particles, dimethylurea, and a gellant is disclosed in U.S. Pat. No. 4,039,360 for a commonly assigned invention issued to Barry D. Allan on Aug. 2, 1977. This thixotropic fuel gel has the ability even with low gellant concentration to maintain metallic fuel particles dispersed therein even under several hundred g's loading. For applications where fuel tank volume is limited, it is desirable to increase the density of the fuel (by adding metallic fuel particles) while maintaining a high specific impulse.
Slurred fuels used in the past can be illustrated by a slurry containing aluminum powder, slurred in a material such as dimethyl hydrazine. The current state-of-the-art of slurred fuel of this sort is to use a liquid fuel, solid metallic additive, and a gelling agent, such as silica.
The primary objective of this invention is to provide a higher energy from metallic fuel gel slurries.